Preventing SQL Injections With Python

For Python developers, it is essential to protect your project from potential SQL injection attacks. SQL injection attacks happen when malicious SQL code is embedded into your application, allowing the attacker to indirectly access or modify data in the database. As you’re probably already aware, such an attack can have disastrous consequences, like data theft and loss of integrity, which is why preventing SQL injection attacks is critical for any web application. 

In this blog post, we will see how you can protect your applications from SQL injection attacks when working with Python. We will also discuss some common techniques that attackers use to exploit SQL injection vulnerabilities, and give you some important tips to prevent such attacks.

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Understanding SQL Injections in Python

An SQL injection is a type of security exploit in which malicious code is inserted into strings that are later passed to an instance of SQL Server for parsing and execution. This malicious code can be used to manipulate the behavior of the database and potentially gain access to sensitive information. 

SQL injections exploit vulnerabilities in the way applications interact with databases. An attacker can insert a command into a web app’s user input, which is then passed to the underlying database for execution. This allows the attacker to bypass authentication mechanisms and gain access to sensitive data or modify its contents. 

For example, an attacker could enter a malicious command that would execute a delete query from a database. The command gets sent to the database for execution, potentially granting the attacker access to data or simply allowing them to delete data from the database. 

Most commonly, hackers will insert malicious SQL commands into user-supplied input fields, such as search boxes and login forms, . An attacker might also use a tool to dynamically generate malicious code and send it to the database.

Luckily, Python provides several methods for preventing SQL injection attacks. 

Related: A Comprehensive Guide To Python Dependency Management

Good Practices to Prevent SQL Injections

There are a few common mistakes developers make that increase the risk of SQL injections, including poor coding practices, lack of input validation, or insecure database configuration. However, with good Python coding practices, developers can drastically reduce this risk. 

To prevent SQL injections from occurring in your application, apply these good habits:

  • Always use parameterized queries when interacting with a database. This ensures that user input is never directly passed to the database, which reduces the risk of an injection attack. Here’s an example of parameterized queries with the help of F-strings:
db_name = "BOOKS"
create_database_query = f"CREATE DATABASE {db_name};"
  • Implement input validation on all user-provided data. This helps to prevent malicious commands from even being executed in the application. By validating the user input, you can quickly detect any suspicious activity and stop it before it even gets to the server, let alone the database. You can do this with the help of try-catch blocks (or try-except ones in Python):
while True:
        num = int(input("Enter an integer 1-10: "))
    except ValueError:
        print("Please enter a valid integer 1-10")
    if num >= 1 and num <= 10:
        print(f'You entered: {num}')
        print('The integer must be in the range 1-10')
  • Ensure that the database is properly configured by implementing the right access restrictions and authentication mechanisms. This includes limiting the access of users with specific permissions and implementing reliable authentication processes.
  • Regularly update your code and any third-party packages you’re using. By regularly patching up your code and checking for vulnerabilities, you ensure that any gateway for an attacker is closed. Since SQL injections are so common, they are frequently patched in most softwares whenever a new version appears, so staying up to date is essential. 
  • Use an intrusion detection system. Although it’s often overlooked, using an intrusion detection system to monitor any suspicious activity or attempts of injection attacks is highly beneficial. These can help identify any malicious activity that could indicate  an attack in progress. 
  • Perform regular security audits of your app’s code and database configuration. This enables you to identify any potential vulnerabilities that could be exploited in an attack.

Learn More: Most Secure Programming Languages 

Final Thoughts

SQL injection is a serious threat to web applications and can have devastating consequences if left unchecked. Preventing SQL injections while working with Python is not that difficult, as long as you stay up-to-date with the latest coding practices and follow the tips we mentioned above. Making sure that your app is secure is not only important for  users, but it also helps maintain the company’s good reputation.

Guy Bar-Gil / About Author

Guy Bar-Gil is an experienced Head of Product-Led Growth and leads product-led growth at Mend. He loves engaging with people to understand and solve complex problems, with a special passion for product and company strategy. Prior to joining Mend, Guy held positions in R&D teams and served as a combat operator in the IDF.